The Design And Implementation Of Bionic Hexapod Robot Motion Control System Based On CPG Model

The structure of the bionic hexapod robot has the characteristics of a large number of joint degrees of freedom and strong coupling between legs.It is important in military transportation,post-disaster rescue and space exploration.However,due to the large number of joint degrees of freedom and strong coupling between legs,the motion control of the robot is difficult.Traditional methods based on the kinematics and dynamics of the robot,which excessively rely on the modeling of robot and environment,and the modeling process are complex.It is difficult to accurately apply the calculation results of kinematics and dynamics to robot motion control.Therefore,the robot motion control method based on traditional modeling not only has a large workload,but also is not conducive to real-time gait control of the hexapod robot.To solve the above problems,the bionic motion control method based on the central pattern generator is selected in this paper.The robot motion control method based on CPG simulates the gait generation of the rhythmic reptile in nature to generate the gait of the multi-legged robot.This control method does not depend on the complex robot modeling process,and has the characteristics of simple control structure,strong real-time performance and diversified gait output.The main research work of this paper includes:Firstly,this paper designed a bionic hexapod robot prototype by imitating the body structure of the hexapod reptile insect,and designed a new four-link bionic hexapod robot leg structure in combination with the leg structure of the insect and the problem of high body weight of the common hexapod robot.This structure uses four-link transmission to replace the naked joints of the legs of common hexapod robots.Without reducing the number of degrees of freedom of the robot,the number of joints of the bionic hexapod robot is reduced,and the body center of gravity of the bionic hexapod robot is reduced.Secondly,the CPG control model of bionic hexapod robot based on Hopf oscillator was established,and the stability and waveform output of Hopf oscillator were studied in detail by single parameter change method.Combined with the characteristics of the leg joints of the hexapod robot designed in this paper,the Hopf oscillator model was improved,the gaitweight matrix was introduced,and the phase difference of the control signal between the six legs of the robot was locked by establishing the loop CPG network topology.Finally,the output results of the simulation model are applied by establishing the mapping function.In order to solve the problem that the gait movement control of the bionic hexapod robot is an open-loop system when walking with CPG motion control gait,a bionic hexapod robot perception system composed of raspberry PI,lidar and laser ranging sensor is designed and built in this paper.By building a robot operating system based on ROS on the raspberry Pi host and running the Hector mapping algorithm in the system,the real-time map of the robot's environment is displayed,and the laser ranging sensor is used to avoid obstacles in the process of movement.Finally,the experimental prototype platform of the bionic hexapod robot was built to verify the design of the gait output and perception system of the CPG model.Experiments show that the experimental results of gait output based on CPG model are good.The robot can walk according to the gait form set in the model,and can avoid obstacles and construct two-dimensional maps of the surrounding environment during walking.The experimental results verify the correctness of the CPG control method and the design of the perceptual system and the feasibility of its application to the actual motion control process.